It’s Alien Day, a special holiday dedicated to celebrating the infamous sci-fi horror action films that gave rise to Ellen Ripley and the towering monstrosity known as the Xenomorph.

Sexual assault analog aside, the Xenomorph is a true horror to behold. It has no recognizable or familiar face aside from a large, gaping maw filled with spiky teeth and a second, telescopic mouth. It’s skeletal, with spindly arms, thick legs, and a long, whiplike tail that trails after it wherever it goes. And the worst part? It’s practically unstoppable.

But in today’s age of entertainment, they’re no longer the onl sci-fi horror game in town. Cross-pollination between film and games has led to a number of terrifying creatures appearing on PCs and consoles, some of which could give the Xenomorph a run for its money to celebrate all things Alien, here’s a look at some of the most terrifying aliens we’ve seen in video games.

Headcrabs (Half-Life Series)

They’re relatively small and look like an over-roasted chicken who sprouted crab legs, but Headcrabs are a dangerous foe .Their goal? To jump up, latch onto your head, and take control of you to command your body as its own vehicle.

Covered in blood and–at least early on–still conscious of your surroundings and susceptible to pain, you’re left wandering with the parasites controlling your actions as you grimly cry out in fear. Not too bad for an alien who only weighs a few pounds.

Xenomorphs (Alien: Isolation)

We’ll overlook the garbage fire that was Aliens: Colonial Marines and consider Alien: Isolation instead, because of its effectiveness at capturing the tension and horror of the original film.

In Isolation, the Xenomorph on the ship is practically unstoppable, and constantly on the hunt for the player. It’s relentless, stalking its prey, traveling through the air ducts of the ship and quietly searching for the player, even when they’re hidden. Along with its terrifying exterior, the Xenomorph is a cold, intelligent creature quick to rip someone out of their hiding spot or impale them with the spear like head at the end of its tail. It is terror incarnate, one of the best movie monsters who continues to terrify today.

Necromorphs (Dead Space Series)

Aside from the whole made-from-humans thing, the Necromorphs have a lot in common with Xenomorphs. They’re both vaguely familiar, yet unsettling-looking creatures, each capable of causing real and serious harm to innocent bystanders.

But it’s more than their twisted, insect-like forms that makes them terrifying. Necromorphs–like Xenomorphs–like to hunt down their prey, claiming it with brutal, violent efficiency. Every noise they make can be horrifying, reverberating around a derelict space ship like a chilling death rattle. They’re dangerous, they’re disgusting, and they’re one of the most recognizable baddies in horror games.

Chryssalids (XCOM: Enemy Unknown)

There’s a special kind of despair linked to the appearance of a Chryssalid in XCOM: Enemy Unknown. These large, scorpion-like creatures have great power that can both be very destructive and turn the tides of a game within a handful of moves.

Not only are Chryssalids obscenely powerful, they’re also capable of murdering a team member and planting an egg inside of them to hatch and completely destroy the freshly-made zombie in several turns. That’s demoralizing on a base level, let alone the fact that witnessing such an event can send some into a panic, thus rendering them as good as useless.

X Parasite (Metroid Fusion)

One of the creepiest inclusions in the Metroid universe, the X Parasite is an alien parasite that assumes the DNA and memories of their host, eventually killing the original organism and continuing to mimic them through their absorbed characteristics.

By themselves, they look like globs of sticky goo you’d find when observing something under a microscope. But they play on one of the greatest scares in science fiction: a complete loss of self and the inability to control one’s actions. The idea of losing control of yourself and eventually ceasing to exist as you once were by force of another organism is a horrible fate indeed.

Banshee (Mass Effect 3)

While all of the corrupted alien species in the Mass Effect series are terrifying, it’s the Banshee that stands out as the ultimate horror. The corrupted version of the elegant Asari, Banshees are spindly and skeletal, with ashen grey skin, gaunt faces, and dead eyes.

They’re incredibly dangerous, capable of doling out punishment through the use of a number of unique attacks. Worse, their attack and movement patterns make them difficult to fight, requiring an extra amount of strategy to engage and successfully kill them. Horror can often be extremely effective when it makes slight adjustments to the familiar, and the Asari transformation into the demonic Banshee is proof.